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This list digest contains the following message subjects:

1. LapDigest News for Issue No. 102 - Thur 1/8/98
2. NEW: Drilling Holes in Lapidary Items
3. RE: Selecting a Cab Machine (was Equipment Query)
4. RE: Selecting a Cab Machine
5. RE: Reusing Cooling Liquid from a Cab Machine
6. RE: Reusing Cooling Liquid from a Cab Machine
7. RE: Reusing Cooling Liquid from a Cab Machine
8. RE: Reusing Cooling Liquid from a Cab Machine
9. RE: Dangers of Cutting Malachite and Others
10. NOTE: Greensboro, N.C. Field Trip
11. FS: Rough Cutting and Carving Material
12. FS: African Cabbing and Gem Rough


Subject: LapDigest News for Issue No. 102 - Thur 1/8/98

If you have topics you wish to see covered, please send them

Stay safe, and have fun!


Subject: NEW: Drilling Holes in Lapidary Items

For several months, I experimented with drilling holes in
lapidary materials, specifically jewelry pendants made out of
very hard agates and jaspers. I tried buying every diamond
drill bit you can find in all the standard jewelry and
lapidary catalogs. After trying all the different brands, I
finally concluded that they all had shortcomings. There were
usually two types offered, sintered and plated. The plated
types were just that: they had diamonds plated onto a thin
wire. Although they were available in coarse grits, they
didn't last worth a hoot, and if you figured out your cost
per hole, it wasn't economical. The sintered type had
diamonds imbedded right in the metal of the bit, but I could
not find any that were coarse enough. Without a coarse grit
diamond, drilling in hard agates was agonizingly slow. Bear
in mind, I was only trying to drill to a depth of maybe 3mm
with a 2.5mm diameter bit, so that a post could be glued into
the hole. Still, without coarse diamonds, it was too slow. I
finally thought of a place where you could buy coarse diamond
drill bits with a small shaft diameter. I called my
*dentist*. I figured he must have to drill into some pretty
hard material, including tooth enamel and old fillings. Sure
enough, he had two or three catalogs from drill bit companies
who supply dentists. Wow! What a selection! There was every
shape, size and grit you could want, and buying directly
through my dentist, the prices were much less expensive than
the inefficient ones I had been buying.

I glued strips of rubber onto the jaws of a small table
vise, and put the vise in an aluminum pan, so the overflow of
water used to lubricate the drill bits could accumulate
there. I used a dremel tool (with variable speed feature)
mounted in a dremel tool drill press, rigged up a water drip
system to lubricate the drill bit(an *absolute must*) , and
set the vise in the pan under the drill press. Using a *very
coarse* dental drill bit at a speed of about 20,000 to 25,000
rpm, I locked the piece of agate in the jaws of the vise, and
started drilling the hole with a fairly rapid up and down
drilling motion, never pressing down very hard at any time.
By just tapping the drill bit rapidly up and down on the
agate, the hole was drilled and constantly lubricated at the
same time. I was able to drill about 8 or 10 holes in the
hardest agate in no time at all. I would estimate that the
*average* time per hole was three minutes. The first holes,
when the diamond was still the coarsest, only took a minute
or two.

When the diamonds finally wear down and the drilling slows
noticeably, I would switch to a new one, but save the old one
for drilling in softer material.

Bear in mind that when drilling in clear or translucent
materials like quartz, the hole will be visible in the
pendant, so only drill as deep as you need to attach a post.

There may very well be good drill bits available in catalogs
I don't know about, but this was my solution. And I'd be
surprised if you can get better prices per bit. For a very
small investment in a dremel tool, or for those with foredom
set-ups, it is an easy way to drill holes quickly and
economically. Unfortunately, I cannot recall the names of the
companies who supplied the dental bits off-hand, but I'm sure
a call to an obliging dentist will answer that question.

I hope this helps some.
Vance McCollum
(Ed. Note: Thanks, Vance. This is a topic which will be
continued over the next several issues, and will cover
special drilling situations. hale)

Subject: RE: Selecting a Cab Machine (was Equipment Query)

I've just completed construction of my Cabmate. I bought the
basic unit & added my own motor & such. My initial plan is to
use an expanding drum with electroplated belts. My question
to experienced cabbers is what would be the recommended grit
belts to purchase. All input is appreciated. Thanks.


Subject: RE: Selecting a Cab Machine


My recommendations for the diamond belts to start with are:-

A. Crystallite 220 grit plated GRINDING belt. The 70 grit
belt is also nice for rapid removal of tough materials, but
expensive. For most things, the 220 works fine.

B. Crystallite 220, 600 and 1800 or 3500 grit SANDING belts.
The sanding belts have the diamond incorporated in plastic
"dots" on the surface of the belts. The finer grit belts
last a lot longer than the coarse ones.

I hope this helps.


Non commercial republish permission granted.

Subject: RE: Reusing Cooling Liquid from a Cab Machine

In a message, you write:

<< ... is it possible to reuse the coolant liquid after it
has been run through (a CabMate, say) and collected in a
bucket? >>

Hello Bob!

Yes, you can. Allowing the sediment to settle out prior to
reusing will make life a little easier on your pump. Take as
much care as possible not stir back up while pouring. The
small particles won't immediately damage the equipment, but
over a period of time it'll wear out parts, kinda like a sand
blaster, only slower.

Vincent King
Fischerstone cabbing materials


Subject: RE: Reusing Cooling Liquid from a Cab Machine

Bob wanted to know about reusing coolant after running it
through a cab mate and saving it in a bucket. There should be
no reason why not. Just let the sediment settle to the bottom
and pour off the clear , clean liquid. then use it. The clean
stuff. I reuse oil in my slab saw all the time by allowing
the sediment to settle and pouring the clear liquid off the
top and putting it back in the slab saw when I clean it.

However in my cabbing machines I use water with just a little
rust inhibitor and can't see any point in saving it. Unless
it is some costly product?

Dixie Reale


Subject: RE: Reusing Cooling Liquid from a Cab Machine

When working with the Cabmate, I use plain tap water for
cooling, so the question of reusing it would only arise in
times of severe drought. If you want to improve the flushing
properties of the coolant, you can add a pinch of dish-washer
detergent (the low foaming stuff), but you could only derive
any benefit from this when using hard diamond wheels or

For use with diamond belts on an expanding drum or with the
"Eurocutter" blades, I find that plain water is entirely

Goeff Haughton

Non-commercial republish permission granted

Subject: RE: Reusing Cooling Liquid from a Cab Machine

Water is about the cheapest chemical we can buy! So cheap,
that I can see no reason to recycle water in a cabbing

Having said that, you might ask whether recycling water could
be harmful. Vince has already noted that it could be harmful
to the pump. Is it harmful otherwise? When I first studied
cabbing, I had to wash my workpiece after every grit wheel,
with a toothbrush. We took great care to keep one grit from
contaminating another grit. But this was with Silicon Carbide
wheels, where the grit can come loose from the wheels.


But how about with diamond wheels? Is this really a problem?

If you look at the Genie, water is held in a tray under the
first three wheels and in another tray under the last three
wheels, and 'spitters' in the trays spray water on the wheels
to cool them. The water in each of the trays is constantly
being recycled. In the Pixie, there is a common tray with
water under all wheels, and this water is constantly recycled
over the wheels through a 'spitter'. As the 'dirty' water
only circulates thru the 'spitter', there is no mechanical
part, such as a pump, which could be harmed. And most of the
'mud' has a chance to settle out in the trays, as anyone who
has cleaned the trays at the end of a working day knows only
too well!

Obviously, when they were designed, Diamond Pacific did not
think that recycling water would harm the work piece.

So I conclude that, with diamond wheels or belts, recycling
water will not be harmful. But why do it with water so cheap?

Non-commercial republish permission granted

Subject: RE: Dangers of Cutting Malachite and Others

In a message, you write:

<<Are there any stones that are dangerous to cut? I've heard
that malachite releases poisonous gases, but I would like to
cut some (someday). Anything else I should be careful

Introducing any foreign body into the lungs COULD be
hazardous. Don't simply try to identify one set of stones as
dangerous. Creating an inordinate amount of dust during the
cutting process is always a bad idea. The Copper Gems, all
inclusive, have their inherent dangers, heavy metal dangers,
if you will. Use an adequate amount of water to assist in
reducing dust. If you can taste it, you're breathing it.

Also take into consideration, that Tigers Eye, Bulls Eye, and
Hawks Eye are all of the Asbestos family.

If you're serious about protecting your lungs through the use
of a mask, don't waste your time and money on the single
layer paper coffee filter type. Their good for keeping gnats
out of the teeth, but that's about it. Take a look for some
of the multi-layered masks designed to keep out fine
particulates. These will be much thicker, have the padded
nose piece to contour to the nose, and two elastic straps one
that fits behind the base of the skull, the other over the
back of the head. Getting the Darth Vader looking
respirators will not only guarantee that you'll be
particulate free, uncomfortable while gemmin', a whole bunch
poorer. The only other benefit would be to scare the hell
out of anyone that comes to visit while you're cutting.

Cutting safely is as easy as using just a touch more water to
control the dust. Can't say it enough, if you can taste it,
you're breathing it!

Happy cutting is NOT hazardous to your health!

Vincent King
Fischerstone cabbing materials

Subject: NOTE: Greensboro, N.C. Field Trip

The Greensboro (N.C.) Gem and Mineral Club January Field Trip
will be to the Geology Department at Guilford College.

This will be an opportunity to get those REALLY hard to
identify minerals figured out, check out the unique equipment,
get guided tours, chat with students and profs about all
aspects of geology.

this field trip is open to all. Guilford college is located
on the corner of Market Street and Guilford College road in
Greensboro. The open house is from 2 to 4 pm on Sunday,
January 26, 1998.

Yes, this is Super Bowl Sunday, but you will be out in plenty
of time for even the preshow. If you would like to come,
please let me know.

Mark Case
Randleman, NC
GGMC VP and Field Trip Chair.

Subject: FS: Rough Cutting and Carving Material

Have another sale of rough cutting and carving material going
on. The list can be requested from me at <>.

Ray Johnson

Subject: FS: African Cabbing and Gem Rough

Hello All:

Please visit our website at the address below.

Minex is also a source of some unusual and rare gem rough
and cut gemstones. We also are a source for gel sugilite
and similar items.

Contact us at <> or in InnSuites
Hotel, Main Lobby for Tucson 1998 Show from Feb. 1 to Feb.


Dirk van Gysen
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